Coating compositions



Patented Aug. 17, 1937 UNITED STATES PATENT OFFICE COATING COMPOSITIONS Nd Drawing. Application March 2 4, 1934,- Serlal No. 717,275

12 Claims.

This invention relates to compositions for coating paper and other sheet material, and is herein described with reference to the provision of a transparent protective coating for printed 5 matter and the like.

An object of the invention is to provide a composition of the desired character which will have a high resistance' to water and moisture, which is not expensive, which has substantially no odor,

which can be applied by machinery at a high rate of speed and still give a uniform but very'thin coating, and which has a pleasing appearance.

I prefer also in most cases to include an ingredient which renders the surface slippery, to fa- 10 cilitate feeding and otherwise handling the coated paper during subsequent operations.

A coating material which forms a coating which is highly resistant to water and moisture includes (dissolved in a solvent such as one or a mixture of benzol, toluol, xylol, or high-flash naphtha), a soluble rubber compound (such as chlorinated rubber), a plasticizer (such as tricresyl phos- Y phate, diamyl phthalate, or the like), an artificial or natural resin, and a wax such as paramne.

I find the most desirable proportions to be four parts of the rubber compound, two and one-half or three parts of the plasticizer, two to three parts of theresin, and one part of the paramne. Onehalf part of mineral oil may, if desired, be added 3 as noted below.

This composition is very advantageous where the utmost in moisture-proofing is desired. On the other'hand, while it has a high degree of tra'nslucence, and-in thin layers is substantially transparent, it has a brown color which restricts its use for some purposes.

On the other hand, where a'fair degree of moisture resistance is sufiicient, a very colorless coating of pleasing appearance can be obtained by 40 dissolving, in the described solvent, processed linseed oil or the like and blown wood oil (preferably three parts of the first to one part of the second), together with a cellulose compound (preferably four parts) such as cellulose nitrate,

cellulose acetate, ethyl cellulose, benzyl cellulose,

or other cellulose ester.

For many purposes, in place of the processed linseed oil and blown wood oil (i. e. such oils which have been heat treated or through which air has been blown until they reach a jeliylike consistency), there may be used soya bean oil, tung oil, perilla oil, castor oil, or mineral oil, similarly processed or treated.

Another very clear solution, which may be used in place of the one just described. includes approximately ten parts cellulose ester, six parts plasticizersuch as tricresyl phosphate or diamyl phthalate, four 'to five parts of a resin such as ester gum, 1 parts parafilne, with parts min- To the'solution so obtained, as noted above,

there may if desired be added a very small quantity of water white clear mineral oil such as that known commercially as special American mineral oil". This oil complies with the U. S. P. requirementsfor White'oil and has a flash point from 380 F. to 385 F., Sayboltviscosity at F. of 280 to 285 seconds, specific gravity of .8871 to .8844 and a pour point of 0 F. This does not solidify when the coating is dried by heating to drive oil the solvent, and neither is it driven oil with the solvent. It remains in the pores of the dried coating, not only adding to the moistureproof effect but also gradually oozing to the surface and keeping it somewhat slippery but without rendering it greasy to the touch. This greatly facilitates handling the coated sheets in subsequent operations, as for example in feeding coated printed blanks to packaging machinery. It also adds greatly to the plasticity ofthe film and reduces' its brittleness, especially when applied topaper.

The foliowing are examples of specific compositions which I have found effective, each being used with the above-described solvent:

1. Parts Cellulose ester 13 Chlorinated rubber 3 Tricresyl phosphate or diamyl phthalate.-- 8 Ester gum 5 Parafline 1. 5 Processed linseed or wood oil a 6 2. v I Pa Cellulose ester 10 Ester g 5 Chlorinated rubber 3 Tricresyl phosphate or diamyl phthalate 5 Mineral oil (if desired) l. '15

3. Parts Chlorinated rubber 8 Tricresyl phosphate or diamyl phthalate 5 Resin such as ester gum 4 Paraiiine 2 Mineral oil (if desired) l .8. Parts Cellulose ester 2 Processed linseed oil 3 Blown (i. e. processed) woo'd oil 1 Chlorinated rubber -1 8 Tricresyl phosphate 6 litter gum resin 4 Paraiiine wax 2 Mineral oil or desired) 1 Chlorinated rubber 8 Tricresyl phosphate or other plasticizer 5 Estergum or otherresin '4 laramne wax 2 Mineral oil (if desired) 1 10. Parts Chlorinated rubber 8 Paraiiine wax 2 Tricresyl phosphate 5 Mineral :oil 2 Ester gum resin 4 'u. I Parts Chlorinated rubber 4 Processed oil 8 Parafllne war 1 12. Parts Cellulose ester 10 Ester gum or other resin 5 Chlorinated rubber e 3 Mineral 01] 2 Plasticizer such as tricresyl phosphate 6 (Note: No. 7 solution is very clear, and as explained above it maybe mixed in any desired proportion with one of the darker compounds having a higher degree 01' moisture-proofing, such-as No. 3 above.)

Parafline wax (of relatively high meltin p int) 2 One well-known commercial form of soluble rubber compound which may be used in these formulae is the chlorinated rubber sold under the name of tornesit. Where it is desired that the coating-be one which will soften with heat, for

example for use in coating wrappers which are to be sealed by heating in the manner now comotherwise than by the terms of the appended claims.

I claim:

1. A coating composition comprising a solvent containing cellulose derivative material of the class consisting of esters and ethers and blown linseed oil and blown wood oil, mixed with a composition containing chlorinated rubber.

2. A composition of matter comprising four parts chlorinated rubber, three parts plasticizer, two parts resin, and one part wax.

3. A coating composition comprising a solvent containing a mixture of cellulose derivative com- 4. Parts may use one of the lower-melting-point "plie- Cellulose ester 4 form" or vinyl or isoprene or other rubber-de- Processed linseed oil 6 rivative resins. Other soluble compounds of rub- 5 Parts her and equivalent rubberlike materials may be cuuloseestr 4 used for special purposes. Processed unseedou 4 The above compositions, usually containing Blown wood on 2 about 50% of sol ds (1. e. material remaining in g the coating after evaporation of a the solvent), 6. Parts may be applied'by the method described and Cellulose ester 4. 2 claimed in my Patent No. 2,000,347, issued May Tricresyl phosphate or diamyl phthalate 2. 5 7, 1935, being applied (preferably under pressure) Ester gum s 2 as a partly-dried viscous coating which, while it Gelled castor 011 1.75 enters the pores of the paper sufiiciently to be Para fi .25 thoroughly bonded thereto, does not enter the Mineral oil (if desired) 25 structure of the paper enough to blur or other- Parts wiseafl'ect the ink making up the printed mat- Cellulose ester 1o the paper- 1 h 1 Plasma 6 312%;gi fiiti tie?diiiiifi ffaeififl if; 3 3, 21? as ester gum 2 not my intention to limit the scope oi. the in- Miwal on (if desired) vention to ,those particular compositions, or

blown linseed oil, blown wood oil, chlorinated rubber, plasticizer, resin and paramne. 1

4. A coating composition consisting of a solvent containing a mixture of two parts cellulose derivative compound of the class consisting of esters and ethers, three parts of blown linseed oil; one part of blown wood oil, four parts chlorinated rubber, three parts plasticizer, two parts resin and one part parafline.

5. A coating composition comprising one part of cellulose derivative material of the class consisting of esters and ethers, at least one fourth part of chlorinated rubber, at least one half part oi. ester gum and at least one half part of plasticizer oi. the class consisting of .tricresyl phosphate and diamyl phthalate.

6. A coating composition comprising one part of cellulose derivative material of the class consisting of esters and ethers, at least one iourth part of chlorinated rubber, at least one half part oi'ester gum and at least one half part of plasticizer or the class consisting oi tricresyl phosphate and diamyl phthalate to which has been added at least one tenth part of mineral oil.

'7. A coating composition comprising one part of cellulose derivative material of the class consisting of esters and ethers, at least oneiourth part of chlorinated-rubbeig'at least one half part of ester gum and at least one half part of plasticizer of the class consisting of tricresyl phosphate and diamyl phthalate to which has been added not more than one part blown oil 01' the class consisting of linseed oil and wood oil and soya bean oil.

8. A coating composition comprising one part of cellulose derivative material of the class consisting of esters and ethers, at least one fourth part of chlorinated rubber, at least one half part of ester gum and at least one half part of plasticizer of the class consisting of tricresyl phos- 2,000,140. phate and dismyl phthalate to which has been.

added not less than one tenth part of parafline wax.

9. A coating composition comprising two parts 5 chlorinated rubber and one part ester gum and at least one part piesticizer of the class consisting of tricreayl phosphate anddiamyl phthalate. 10. A coating composition comprising eight parts chlorinated rubber, five pert: tricresyl i0 phosphote, four parts ester gum.-

- m phosphate.

11. A coating composition comprising thirteen parts cellulose ester, three parts chlorinated rubher, five parts ester gum and eight parts tricre- 12. A coating composition comprising eight parts chlorinated rubber, five parts tricresyl phosphate, four parts ester gum to which has been added two parts paramne 'wax and one part mineral oil.

JOHN D. MURRAY. 

